1. Field of the Invention
The present invention relates to an optical character reader for reading a character, a symbol or the like by scanning a paper with a hand-held scanner. A hand-held optical character reader is often used for a POS (point of sales) system in which pieces of information on the sales of article are collected in a supermarket, a department store or the like to control its inventory.
2. Description of the Prior Art
Such a hand-held optical character reader was disclosed in Japanese Patent Publication No. 6418/84. In that reader, an image sensor having a plurality of photoelectric conversion elements disposal thereon is first used to scan a character, a symbol or the like to recognize it. A vertical character range is then scanned to determine if at least one image element signal indicating the presence of a character portion exists in each of a predetermined number of rows. The rows are represented by binary signals that are generated by scanning appears in a prescribed sequence over a prescribed number of rows.
Before or after the detection of the vertical character range, a horizontal character range is scanned by determining whether at least one image element signal indicating the presence of a character portion exists in each of a predetermined number of columns which are represented by the binary signals generated by the scanning. Whether the scan of the horizontal range detects the presence of a particular character is determined by whether a prescribed sequence of signals is detected over a prescribed number of columns.
In this manner, characteristic data on the characters is extracted as to each row or column within the vertical and horizontal character ranges. Recognition processing is then performed responsive to the characteristic data in order to output a character recognition determination.
Since the field of vision of such prior art optical character readers can cover only one character at one time, the scanner of the reader needs to be moved horizontally, one by one, over a line of characters to read the characters. For that reason, a character will not be properly scanned and recognized if it is partially out of the field of vision of the reader during the movement of the scanner. Consequently, such prior art character readers frequently misidentify characters, or fail to detect certain characters completely.